19 Oct 10

This is a disease of growing importance for all dog owners in Hong Kong.  Due to the increase mobility of dogs with their owners, especially in a cosmopolitan place such as Hong Kong, the incidence of canine Heartworm disease is on the increase.  All it takes for an infection to occur is the presence of an already infected dog and the transmitter of the disease, the mosquito.

這種致命的病在香港日漸普遍,本地的狗主應該多加注意.在香港這樣的大城市,狗隻經常都要隨著主人搬家,染上這種病的個案日增.  狗隻染上這種病並不困難,只要附近有一隻已經受感染的狗,和有蚊蟲出沒就可以了.

Life Cycle of the Canine Heartworm 犬心蟲的生命循環週期

1. Adult male and female heartworms are usually found in the lung arteries and the right hand side of the heart.  The female will produce first stage larvae or microfilariae into the bloodstream.  These 1st stage microfilariae are ingested by the mosquito when it takes a blood meal.

1)成年的雌雄犬心蟲通常寄居在肺動脈和右心房,雌性犬心蟲會將第一期的幼蟲或者微絲蚴產生進血管中.當蚊蟲吸食狗隻的血時,會同時吸進這些微絲蚴.

2. The 1st stage microfilariae will develop into 2nd and then 3rd stage microfilariae in the mosquito within the first 8-17 days.

2)第一期的微絲蚴在蚊蟲的體內,發育成第二期和第三期的微絲蚴.這段時期約需八至十七天.
3. When the mosquito feeds on another dog it will pass the 3rd stage microfilariae into the bloodstream, thereby infecting the new dog.

3)這隻蚊蟲再吸食另一狗隻的血時,即將第三期的微絲蚴帶進狗隻的血管內,這樣又有一隻狗隻受到傳染.

4. The 3rd stage microfilariae in the dog continues developing for 3-4 months prior to reaching their final destination, the heart.

4)第三期微絲蚴繼續在狗隻體內發育,三四個月後才游至最後的寄居地——–心臟.

5. Once in the heart the young heartworms develop into full adults and the females will start producing more infective 1st stage microfilariae in 5-6 months.

5)青年期的犬心蟲一旦抵達狗隻的心臟,即發育成成蟲.五六個月後,雌性犬心蟲會產下第一期的微絲蚴, 這樣又開始另一個感染循環.

Clinical Symptoms 臨床病徵

The earliest signs of canine Heartworm disease include coughing, laboured breathing, weakness and increasing exercise intolerance.  Due to the presence if the adult heartworms in the right ventricle and pulmonary arteries of the heart, there is an increase resistance to the flow of blood, thereby causing the blood pooling in the liver and spleen.  If there is a high count of adult heartworms the dog may develop congestive heart failure.

犬心病的早期病徵包括咳嗽,呼吸沉重,體弱,漸漸不肯做多些運動.由於成年犬心蟲寄生在心臟的肺動脈和右心室,阻礙了血液流通,令肝臟和脾臟充血.若成年犬心蟲的數目眾多,會令狗隻患上充血性心力衰竭.

Diagnosis 診斷

A diagnosis can be based on an examination of blood sample microscopically.  Confirmation is usually done with the use of an antigen test using a fresh blood sample.

診斷的方法是抽取血液樣本,以顯微鏡找出微絲蚴,或用快速犬心蟲抗原測試來確診.

Treatment/Prevention 治療

The best treatment is to prevent the infection in the first place. The most common treatments include a monthly oral treatments or yearly injectable treatment. 

最佳的治療方法是預防. 常用的預防方法包括每月一次的口服預防藥物或每年一次的心絲蟲預防針。

If the dog already has an established colony of adult heartworm, treatment can be quite risky, time consuming and relatively expensive.  Treatment involves treatment with drugs which could potentially cause adverse reactions.  Fatalities are possible if the patient is very sick.

如果狗隻體內已有犬心蟲成蟲群,治療的過程就會頗危險,而且需要花上很長的時間,費用很昂貴. 治療犬心蟲用的藥有可能會引起副作用.嚴重染病的狗隻甚至會死亡.

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